Ready to upgrade D70 and/or glass
After many years enjoying my trusty D70, I am finally thinking about upgrading. Currently, I use the 17-80mm kit lens and the 50mm f1.8 AF lens, which I love. Also have the SB-400 flash. I fully intend to keep my D70 in service, but would appreciate advice on what my next purchase(s) should be. I tend to crop a lot, and thus would love some extra resolution to work with, as well as video capability and better high ISO performance. However, I also understand the beauty of investment in glass, and some extra reach would be great as well. I've been looking at the D5100, as well as everything from the Sigma 18-250 lens, to one of those sexy f2.8 zooms which I can't afford lol.
Any advice on what my next purchases should be would be appreciated. I am happy to carry around 2 cameras to minimize lens swapping, and want to pair the right lens with the right camera, which camera should get the flash, etc. FYI, I am not a pixel peeper, and thus the lens doesn't have to be exceptionally sharp, as most of my work is viewed online (I mostly shoot school events). I am more interested in fast AF so I don't miss a shot. As for budget, I'd really like to keep costs down, but am open to investing. What I don't want is to purchase something that I hate, as I made the mistake on a cheap 70-300 Tamron years ago (non-vr/os, terrible AF wait time) that now sits as a decoration on my bookshelf lol.
Thanks so much!